|
One Way ANOVA is used to determine whether varying the levels or values of a single factor affect a process. The following data show the strength of a fibre with varying percentages of a synthetic material:
| |
1
|
2
|
3
|
4
|
5
|
|
15%
|
8 .7
|
9.8
|
12.2
|
12.9
|
9.5
|
|
20%
|
14.5
|
17.3
|
14.9
|
15.5
|
12.7
|
|
25%
|
16.0
|
13.8
|
18.3
|
17.2
|
18.0
|
|
30%
|
23.8
|
21.5
|
18.3
|
24.3
|
22.9
|
|
35%
|
9.0
|
14.3
|
10.0
|
14.3
|
7.1
|
An ANOVA analysis tests the hypothesis:
H0 The fibres are all of equal strength
H1 At least one of the fibres is of different strength
The analysis is:
|
Source of Variation
|
Sum of Squares
|
Degrees of Freedom
|
Mean Square
|
F0
|
p-value |
|
Factor
|
448.32
|
4
|
112.08
|
21.78
|
0
|
|
Error
|
102.91
|
20
|
5.15
|
|
|
|
Total
|
551.23
|
24
|
|
|
|
The alternative hypothesis is accepted, at least one of the fibres has a different mean strength.
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